Endorphins (“endogenous morphine”) are endogenous opioid peptides that function as inhibitory neurotransmitters. They are produced by the pituitary gland and the hypothalamus in vertebrates during exercise, excitement, pain, spicy food consumption, love, and sexual activity, and they resemble the opiates in their abilities to produce analgesia and a feeling of well-being.
The term implies a pharmacological activity (analogous to the activity of the corticosteroid category of biochemicals) as opposed to a specific chemical formulation. It consists of two parts: endo- and -orphin; these are short forms of the words endogenous and morphine, intended to mean “a morphine-like substance originating from within the body.”
The term “endorphin rush” has been adopted in popular speech to refer to a feeling of exhilaration that can be brought on by pain, danger, or other forms of stress, supposedly due to the influence of endorphins. When a nerve impulse reaches the spinal cord, endorphins prevent nerve cells from releasing more pain signals.